1. Field of the Invention
This invention relates to an inspirator for a burner of an infrared heater, the inspirator having a bore with a plurality of successively larger steps downstream of a venturi.
2. Description of the Prior Art
Inspirators for burners and heaters are known and have a fuel inlet and air inlet in a bore that narrows to a venturi and smoothly expands downstream of the venturi to achieve a combustible fuel air mixture. Inspirators are often cast from metal or made from ceramics. Previous inspirators are fragile and are easily damaged and are usually used to power a burner, heater or furnace in which an open flame is created. Inspirators are expensive. Cast metal is much more brittle than the uncast metal. Cast metal of the venturi body and ceramic venturi bodies are subject to premature failure if they are not handled with extreme care as they can easily break or crack. When a venturi body breaks or cracks, the heater must be shut down for repair. The down time can be extremely inconvenient and expensive. The conditions under which a heater is used often involve sudden movement, changes in direction and slamming the heater against a supporting surface, all of which can cause the inspirator or venturi body to break or crack. A gas fired radiant heating unit is described in U.S. Pat. No. 6,669,467, (which is incorporated herein by reference). Sometimes a venturi will crack, but the crack will not be noticeable. This can lead to incomplete combustion, contamination of the environment and can also be a safety hazard for workers at the site where the venturi body and heater/burner is being used.